TACOMA — Lacey Phillabaum was a champion high-school debater who majored in art history at the University of Oregon. Jennifer Kolar's scientific bent took her to the University of Colorado, where she pursued a doctorate degree and attended climate conferences.

They were both members of the elusive underground of the Earth Liberation Front, which early on the morning of May 21, 2001, set off a firebomb that caused $7 million in damages at the University of Washington's Center for Urban Horticulture.

On Wednesday in U.S. District Court in Tacoma, Phillabaum and Kolar pled guilty to participating in the UW arson and other crimes. They pledged their cooperation in a continuing federal investigation into a series of other arsons and attacks on property by Earth Liberation Front (ELF) and the Animal Liberation Front (ALF) across the West.

Under the terms of separate plea agreements, prosecutors will recommend that Kolar, 33, of Seattle, receive a federal prison sentence of five-to-seven years, and a three-to-five-year term for Phillabaum, 31, of Spokane. The two were released without bail following their pleas.

"These violent acts of destruction are not a valid form of political speech," said U.S. Attorney John McKay. "We hope that these significant prison terms will dissuade others."

Both women faced a minimum of 30 years in prison if they had gone to trial and been convicted of all counts listed in their plea agreements.

The separate court hearings and briefings by the U.S. attorneys Wednesday offered the most detailed accounts yet of the people and events that led to one of the most high-profile and controversial of the Earth Liberation Front attacks.

The ELF sought to target genetically-engineered poplar trees at the UW. But the attacks ended up destroying other research projects, include wetlands restoration and endangered stickweed plants.

The attack reflected a shift in focus from earlier eco-sabotage acts. The FBI had ranked the ELF and the ALF as among the nation's top domestic terrorism threats after a string of attacks beginning in 1996 against U.S. Forest Service buildings, a Vail, Colo., ski resort, a wild horse slaughterhouse and other targets.

In 2000, in an attempt to recruit more people to join their attacks, the ELF held a series of secret meetings in Oregon, California, Arizona and Washington. At those meetings, they agreed to target companies and government facilities involved in genetic engineering, according to court documents.

The biggest strike was a planned, early morning double-hit on May 21, 2001, against genetically-engineered poplar, fast-growing trees used for pulp and lumber.

The targets were an Oregon poplar farm owned by a timber firm and the Center for Urban Horticulture office of UW professor Toby Bradshaw, who received timber-industry funding for poplar research.

The ELF's news release, issued five days after the arson attacks, said the poplars pose "an ecological nightmare" for the diversity of native forests.

The UW attack was planned at a secret meetings in Olympia, where a garage had been fashioned into a "clean room," to manufacture time-delayed fire bombs, according to Andy Friedman, a U.S. assistant attorney for Western Washington.

At the hearing, Kolar admitted she used a knife to cut glass so others could get into Bradshaw's office. Phillabaum admitted to being on-scene, but her role in the attack was not detailed.

Three other people were at the scene of the attack, according to federal prosecutors.

• Bill Rodgers, 40, considered to be one of the top organizers of the ELF and a hands-on participant who allegedly help set the fire bombs inside the UW horticulture center. Rodgers, a bookstore operator in Prescott, Ariz., was taken into federal custody last December, then committed suicide in an Arizona jail. He has been implicated in at least nine attacks, including the 1998 fire bombing in Vail that caused $12 million worth of damage.

• Justin Solondz, 27, who once lived on the Olympic Peninsula, allegedly helped assemble the fire bombs in an Olympia garage converted into a clean room, and joined Rodgers in setting the devices inside Bradshaw's office. Solondz is now a fugitive.

• Briana Waters, 30, of California, served as a lookout and has been indicted for her role in the arson. She is expected to face trial on charges that include use of a destructive device in a crime of violence. If convicted of that charge, she faces a minimum of 30 years in prison.

Bradshaw, the professor who was the target of the attack, said Wednesday that the fire burned his office, but his main loss was books and personal effects, rather than research. He had some 80 genetically-engineered poplar trees stored in a separate greenhouse that was undamaged by the fire.

The fire took the biggest toll on the work of some two dozen colleagues involved in a wide range of plant research destroyed by the fire.

"The truth is that we're dealing with a bunch of misinformed ... folks who don't understand the research that was being carried out," Bradshaw said. "Even though I was the target, I am the one who was least affected."

The rebuilding of a new, $7.2 million horticultural center was completed in 2004.

At separate hearings in Tacoma, Kolar and Phillabaum offered short answers to questions from a judge reviewing the details of the plea agreement.

Kolar was composed throughout her hearing. Phillabaum offered a long silence and choked back tears before her first response. Soon, her voice grew stronger.

Both Kolar and Phillabaum graduated from Shadle Park High School in Spokane, but it is unclear whether the two women knew each other there.

Kolar is the daughter of a contract writer for a publishing company and became an activist after moving to Boulder, Colo., to attend college there, said her ex-husband Dominik Minier, of Spokane.

"She had been a vegetarian, but she started getting a lot more serious about veganism. She said she couldn't wear leather sandals or leather jackets," Minier said. "It seemed like more and more she was going off the edge with it."

Phillabaum is "bright, articulate and passionate about what she believes in," said her father, Steve Phillabaum, of Spokane.

He said his daughter has spoken frankly about the arson.

"Everybody realizes that Lacey made a mistake years ago and we're proud of her for acknowledging that, and dealing with what she did openly, honestly and appropriately," he said.